2 2
LEARNING OUTCOME
LEARNING OUTCOME
1.1 CELL THEORY 1.1 CELL THEORY **Describe**Describe the cells the cells as the as the smallest smallest independent independent unit unit of of lifelife and form the basis of living
and form the basis of living organisms.organisms.
1.2 PROKARYOTIC AND EUKARYOTIC CELLS
1.2 PROKARYOTIC AND EUKARYOTIC CELLS
**Compare the structure of prokaryotic & eukaryotic cells **Compare the structure of prokaryotic & eukaryotic cells
1.3 PLANT AND ANIMAL CELLS
1.3 PLANT AND ANIMAL CELLS
**Detailed structure ( plant and animal ) **Detailed structure ( plant and animal ) **Compare plant and animal cells
**Compare plant and animal cells 1.4 CELLS AS BASIC UNIT OF LIVING
1.4 CELLS AS BASIC UNIT OF LIVING ORGANISMSORGANISMS
**Specialized cells. **Specialized cells. a)
a) plant plant ±± meristmeristem,parem,parenchymenchyma,collenca,collenchymhyma,sclera,sclerenchyenchymama b) a
b) aninimamal ±l ± epepititheheliliumum, n, nererveves, ms, mususclcle, ce, cononnenectctivive te tisissusuee
--(DESCRIPTION OF STRUCTURE FUNTION AND DISTRIBUTION) (DESCRIPTION OF STRUCTURE FUNTION AND DISTRIBUTION)
LEARNING OUTCOME
LEARNING OUTCOME
1.1 CELL THEORY
1.1 CELL THEORY
**Describe
**Describe the cells the cells as the as the smallest smallest independent independent unit unit of of lifelife and form the basis of living
and form the basis of living organisms.organisms.
1.2 PROKARYOTIC AND EUKARYOTIC CELLS
1.2 PROKARYOTIC AND EUKARYOTIC CELLS
**Compare the structure of prokaryotic & eukaryotic cells **Compare the structure of prokaryotic & eukaryotic cells
1.3 PLANT AND ANIMAL CELLS
1.3 PLANT AND ANIMAL CELLS
**Detailed structure ( plant and animal ) **Detailed structure ( plant and animal ) **Compare plant and animal cells
**Compare plant and animal cells 1.4 CELLS AS BASIC UNIT OF LIVING
1.4 CELLS AS BASIC UNIT OF LIVING ORGANISMSORGANISMS
**Specialized cells. **Specialized cells. a)
a) plant plant ±± meristmeristem,parem,parenchymenchyma,collenca,collenchymhyma,sclera,sclerenchyenchymama b) a
b) aninimamal ±l ± epepititheheliliumum, n, nererveves, ms, mususclcle, ce, cononnenectctivive te tisissusuee
--(DESCRIPTION OF STRUCTURE FUNTION AND DISTRIBUTION) (DESCRIPTION OF STRUCTURE FUNTION AND DISTRIBUTION)
3 3
CELL THEORY
CELL THEORY..
THEORY;
THEORY;
±± All living organisms are composed of one or moreAll living organisms are composed of one or more cells.
cells. ±
± Cells-Cells- basic unbasic units of its of structure structure and functand function in ion in anan organism.
organism. ±
± cells have the same chemical composition.cells have the same chemical composition. ±
± Cells come only from reproduction of existingCells come only from reproduction of existing ce
celllls-s- mimitotosisiss ±
± GeneGenetic mattic materiaerials-ls- pass to dapass to daughteughter cells durir cells duringng cell division.
cell division. ±
± P/S P/S ±± virus/chloroplvirus/chloroplast/mitochoast/mitochondria handria have ve their their own DNA
1.2
Prokaryotic And Eukaryotic Cells
TYPES OF CELLS
± Prokaryotic (prokaryote)
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Prokaryotes
Pro = before; karyon = nucleus Single celled organism
relatively small ± 0.5 to 10 um lack membrane-bound organelles earliest cell type
No nucleus/ no nuclear envelope
E.g.; bacteria/yanobacteria(blue ±green algae) Surrounded by cell wall
Eukaryotes
Eu = true; karyon = nucleus 10-100 micrometer
contain membrane-bound
organelles
Evolved from prokaryotes by
endosymbiotic association of two or more prokaryotes
Include Protists, Fungi, Animals,
and Plants ( cell wall made of cellulose)
E.g.; Protist/fungi/animal and
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Features of Prokaryotic Cells
Cytoplasm
± semi-fluid cell interior
± no membrane-bound organelles ± location for metabolic enzymes
± location of ribosome for protein synthesis
Ribosome.
± The smaller (70 S) type.
Nucleoid
± region where naked DNA is found
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DNA.
± Always circular, and not associated with any proteins to form chromatin ± naked DNA
Plasmid.
± Small circles of DNA, used to exchange DNA
between bacterial cells, and very useful for genetic engineering.
Cell membrane.
± made of phospholipids and proteins, like eukaryotic membranes- separates the cell from the environment
Mesosome.
± A tightly-folded region of the cell membrane containing all the membrane-bound proteins required for respiration and
photosynthesis.
± Can also be associated with the nucleoid.
Cell Wall.
± Made of murein (not cellulose), which is a glycoprotein (i.e. a protein/carbohydrate complex, also called peptidoglycan).
± There are two kinds of cell wall, which can be distinguished by a Gram stain: Gram positive bacteria have a thick cell wall and stain purple, while Gram negative bacteria have a thin cell wall with an outer lipid layer and stain pink.
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Cell Wall
± rigid structure - maintain its shape (made of peptidoglycan)
Capsule (or Slime Layer ).
± A thick polysaccharide layer outside of the cell wall, like the glycocalyx of eukaryotes.
± Used for sticking cells together, as a food reserve, as protection against desiccation and chemicals, and as protection against phagocytosis.
Capsule
± outer sticky protective layer
± this is in NO way the same as the cell wall of a plant cell
Flagellum.
± A rigid rotating helical-shaped tail used for propulsion(movement)
± The motor is embedded in the cell membrane and is driven by a H+ gradient across the membrane.
± Clockwise rotation drives the cell forwards, while anticlockwise rotation causes a chaotic spin.
± This is the only known example of a rotating motor in nature.
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Cytoplasm (or Cytosol).
± This is the solution within the cell membrane.
± contains enzymes -glycolysis (part of respiration) and other metabolic reactions together with sugars, salts, amino acids, nucleotides and everything else needed for the cell to function. ± All living content excluding nucleus and plasma membrane
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Nucleus.
± largest organelle.
± Surrounded by a nuclear envelope-double membrane with nuclear pores - large holes containing proteins that control the exit of substances (RNA
/ribosomes)from the nucleus.
± The interior is called the nucleoplasm, which is full of chromatin- a DNA/protein complex in a 1:2 ratio
containing the genes.
± During cell division the chromatin becomes
condensed into discrete observable chromosomes. ± The nucleolus is a dark region of chromatin, involved
in making ribosome.
Mitochondrion (pl. Mitochondria).
± sausage-shaped organelle (8µm long)-where aerobic
respiration takes place in all eukaryotic cells.
± Mitochondria are surrounded by a double membrane: the outer membrane is simple and quite permeable, while the inner membrane is highly folded into cristae-large surface area.
± The space enclosed by the inner membrane is called the mitochondrial matrix, and contains small circular strands of DNA.
± The inner membrane is studded with stalked particles, which are the site of ATP synthesis.
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Chloroplast.
± Bigger/fatter than mitochondria, chloroplasts-site of photosynthesis,-only found in photosynthetic
organisms (plants and algae).
± enclosed by a double membrane, also have a third
membrane (thylakoid membrane)-folded into thylakoid disks which then stacked into piles( grana)
± The space between the inner membrane and the thylakoid is called the stroma.
± The thylakoid membrane contains chlorophyll and other photosynthetic pigments arranged in
photosystems, together with stalked particles, and is the site of photosynthesis and ATP synthesis.
± Chloroplasts also contain starch grains, ribosomes and circular DNA.
Ribosomes.
± These are the smallest and most numerous of the cell organelles, and are the sites of protein synthesis.
± They are composed of protein and RNA, and are manufactured in the nucleolus of the nucleus.
± Ribosomes are either found free in the cytoplasm-site of proteins synthesis for the cell's own use, or they are found attached to the rough endoplasmic
reticulum, where they make proteins for export from the cell.
± They are often found in groups called polysomes.
± All eukaryotic ribosomes are of the larger, "80S", type.
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Smooth Endoplasmic Reticulum (SER).
± Series of membrane channels involved in
synthesizing and transporting materials, mainly lipids, needed by the cell.
Rough Endoplasmic Reticulum (RER).
± Similar to the SER, but studded with numerous ribosomes, which give it its rough appearance. ± The ribosomes synthesis proteins, which are
processed in the RER (e.g. by enzymatically modifying the polypeptide chain, or adding
carbohydrates), before being exported from the cell via the Golgi Body.
Golgi Body (or Golgi Apparatus).
± Another series of flattened membrane vesicles, formed from the endoplasmic reticulum.
± F(x)transport proteins from the RER to the cell membrane for export.
± Parts of the RER containing proteins fuse with one side of the Golgi body membranes, while at the other side small vesicles bud off and move towards the cell membrane, where they fuse, releasing their contents by exocytosis.
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Vacuoles.
± These are membrane-bound sacs containing water or dilute solutions of salts and other solutes.
± Most cells can have small vacuoles that are formed as required, but plant cells usually have one very
large permanent vacuole that fills most of the cell, so that the cytoplasm (and everything else) forms a thin layer round the outside.
± Plant cell vacuoles are filled with cell sap, and are very important in keeping the cell rigid, or turgid. ± Some unicellular protoctists(protist) have feeding
vacuoles for digesting food, or contractile vacuoles for expelling water.
Lysosomes.
± These are small membrane-bound vesicles
formed from the RER containing a cocktail of
digestive enzymes.
± They are used to break down unwanted
chemicals, toxins, organelles or even whole
cells, so that the materials may be recycled.
± They can also fuse with a feeding vacuole to
digest its contents.
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Cytoskeleton.
± This is a network of protein fibres extending throughout all eukaryotic cells, used for support, transport and motility.
± The cytoskeleton is attached to the cell membrane and gives the cell its shape, as well as holding all the organelles in position. ± There are three types of protein fibres (microfilaments,
intermediate filaments and microtubules), and each has a corresponding motor protein that can move along the fibre carrying a cargo such as organelles, chromosomes or other cytoskeleton fibres.
± These motor proteins are responsible for such actions as:
chromosome movement in mitosis, cytoplasm cleavage in cell division, cytoplasmic streaming in plant cells, cilia and flagella movements, cell crawling and even muscle contraction in
animals.
Centriole.
± This is a pair of short microtubules involved in
cell division.
± Before each division the centriole replicates
itself and the two centrioles move to opposite
ends of the cell, where they initiate the spindle
that organises and separates the
chromosomes.
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Undulipodium (Cilium and Flagellum).
± This is a long flexible tail present in some cells and used for motility.
± It is an extension of the cytoplasm, surrounded by the cell membrane, and is full of microtubules and motor proteins so is capable of complex swimming
movements.
± There are two kinds: flagella (no relation of the
bacterial flagellum) are longer than the cell, and there are usually only one or two of them, while cilia are
identical in structure, but are much smaller and there are usually very many of them.
Microvillus (MICROVILLI)
± These are small finger-like extensions of the cell membrane found in certain cells such as in the epithelial cells of the
intestine and kidney, where they increase the surface area for absorption of materials.
± They are just visible under the light microscope as a brush border.
Cell Membrane (or Plasma Membrane).
± This is a thin, flexible layer round the outside of all cells made of phospholipids and proteins.
± It separates the contents of the cell from the outside
environment, and controls the entry and exit of materials.
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Cell Wall.
± This is a thick layer outside the cell membrane used to give a cell strength and rigidity.
± Cell walls consist of a network of fibers, which give strength but are freely permeable to solutes (unlike membranes).
± A wickerwork basket is a good analogy.
± made mainly of cellulose, also contain hemicelluloses, pectin, lignin and other polysaccharides.
-built up in three layers > primary cell wall, the secondary cell wall and the middle lamella.
± There are often channels through plant cell walls called
plasmodesmata, which link the cytoplasms of adjacent cells. ± Fungal cell walls are made of chitin (poly-glucosamine).
± Animal cells do not have a cell wall, though they do have a layer of carbohydrate outside the cell membrane called the cell coat, or glycocalyx.
Microscopic structures of plant
and animal cells
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COMPARISON- PROKARYOTIC&
EUKARYOTIC CELLS
CHARATERISTICS PROKARYOTES EUKARYOTES 1. SIZE Small cells ,diameter-0.5-5micrometer Large cells, up to 40
micrometer
2.DNA Circular & free in cytoplasm-naked DNA DNA is associated with histone protein to form chromosome
3.NUCLEUS Not enclosed by membrane-naked Bounded by membrane(
nucleus envelope)
4.ORGANELLES No membrane bound organelles/ no
centriols and microtubules
Has membrane bound organelles;
mitochondria,chloroplast,centri ols.etc.
5.RIBOSOMES Small ( 70s) large (80 s)
6.CELL WALL Present- made up from peptidolican Only plant(cellulose), fungi and chitin
7.FLAGELLA Present- movement Absent 8.CELL DIVISION Simple fission Mitosis
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Tissue and Organs in plant:
± Dermal Tissue System (epidermis)-forms the
outer layer of a plant.
± Ground Tissue System
(parenchyma/collenchyma/sclerenchyma)-(makes up the bulk of roots and stems
± Vascular Tissue ( xylem& phloem)-transports
water and food throughout the plant.
The FOUR Plant Organs are ROOTS,
Specialized cell : Plant
Meristem
Meristems- cells that undergo repeated division.
These are the cells from which all other cells in the plant originate. No undergoes differentiation.
2 types of meristem : 1) apical>shoot and root
2) lateral>cambia-vascular cambium -cork cambium
three types : primary, secondary, and pericycle .
The primary meristems give rise to primary tissues in the plant, which elongate the plant by either shoots or roots.
Secondary meristems form the basis of secondary tissues that enlarge the diameter of the stem or root.
the pericycle is a specialized meristem-found only in the root system-gives rise to branch roots.
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Meristem, parenchyma, collenchyma,
sclerenchyma, xylem, and phloem tissues
Parenchyma
± Unspecialized and are found in all organs of plant.
Can divide and give rise to more specialized cells. Living at maturity
Isodiametrical/ polyhedral(many sided)-capable 4 cell division Thin 1st cell wall and without 2nd cell walls
Loosely packed
Involved in food storage.
Involved in apoplast pathway 4 mvment of water and minerals. Divide to 4 type: 1) epidermis
2) mesophyll
3) endodermis 4) pericycle
Collenchyma
- thicker primary walls. - Polygonal shape
- f(x) : mechanical support
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Sclerenchyma
± Sclerenchyma cells have thick secondary walls impregnated with lignin. ± Most are non living.
± More rigid than collenchyma cells
± Most cells death at functional maturity ± Can be divided into 2 types:
a) fibres- elongated
b) scelereids( stone cells ) - spherical - can be found in the cortex, pith and phloem * Function ± supporting element of the plant
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X
ylem
X
ylem transports water and minerals from
the roots to the leaves.
± Tracheids
elongated, with tapered ends and have lignified
walls
Matured cells death with empty lumen
± Pits in end walls. ± Vascular rays ± Fibers
± Vessel Elements
Larger, with perforated plates in their end walls.
Long ,narrow tube formed
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Phloem
Phloem transports sucrose and other organic
compounds from the leaves to the roots.
± Sieve-tube members are conducting cells.
Contain cytoplasm but no nuclei. Channels in end walls.
Plasmodesmata extend from one cell to another through
sieve plate.
Companion cells- contain nucleus, vacuoles, ribosomes and
mitochondria
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PARENCHYMA CELLS Characteristic :
>Living and unspecialized
>isodiametrical,sometimes elongated
>Composition :cellulose, pectins and hemicellulose, covering of cutin
>Large central vacuole with cytoplasm pushed to side of wall >Thin cell wall
>Loosely packed, large intercellular air space Function :
> Provided support in herbaceous plant > Gaseous exchange
> Food storage
> Replacement of injured and damage cells Distribution :
>Cortex ,pith , medullary rays ,packing tissue in xylem and phloem
SPECIALIZED PARENCHYMA
1) Epidermis : single layer covering plant body, elongated and flattened, protection against desiccation and infection
2) Mesophyll : between upper and lower epidermis of leaves
3) Pericyle : between central vascular tissue and
endodermis in roots,isodiametrical,retain meristematic activity giving rise to lateral root and 2ndgrowth
4) Endodermis :singled celled betwn outer cortex and
inner pericycle tissue; impregnated suberin forming
Casparian strip which prevent passage of water via apoplast pathway
COLLENCHYMA CELLS Characteristic :
> Living , unevenly thickened (extra cellulose at corners of he cells)
> Polygonal and elongated with tapering ends
> Composition: cellulose , pectins and hemicelluloses > small intercellular air spaces@ non exist
Function:
> support And mechanical strength
Distribution : Outer region of cortex: below epidermis
SCLERENCHYMA CELLS Characteristic :
> Polygonal and elongated with tapering ends, tightly packed with no intercellular air spaces
> Deposits of lignin on 1st cell wall resulting
in death matured cells ; incapable of elongation at maturity
Function :
> support and mechanical strength
:provided great tensile and compressional strength as a result of deposits of lignin at cellulose cell wall
2 types of sclerenchyma cells : fibre and sclereids
Sclerenchyma fibre : elongated, polygonal with tapering ends, death at maturity, no protoplasm ,narrow empty lumen, pit present, tapering ends overlapping and interlocked with one another thus provided mechanical strength
Scelereids(stone cells): shorter than fibres , dead cells with thicker lignified cell wall, simple pit present , found in stems,leaves, fruits and provide strength and support plant structures and organs
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Epithelial cell/ epithelium
One of the simplest tissues.
However, it can be built up into tissues of
varying complexity.
Lining tissues : in it simplest form, it consists of a
single layer of cells covering the surface of the
body and the organs within it.
Epithelial cell
Also lines various spaces and tubes ( in
which situation it is usually referred to as
endothelium).
Typically the individual cells : firmly
attached to each other.
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Epithelial cell
rest on a basement membrane.
have a free surface
The main function of epithelial tissues is
protection.
Epithelial cell
Other functions:
To increase the surface area for the
reabsorption of materials/which absorption
can take place.
Exchange materials by diffusion.
As a gland ; secrete mucus or enzyme.
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Types of Epithelial Tissues
Simple
Epithelial
Tissues
Stratified
Epithelial
Tissues
Pseudostratified
Epithelial
Tissues
Epithelial
Tissues
Simple Epithelial Tissues
1. Simple squamous epithelial tissues.
2. Simple cuboidal epithelial tissues.
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Simple squamous epithelial tissues
Cells are flattened.
Disc- shape nucleus
Functions:
exchange of material/protect underlying tissues
lubricates the movement between adjacent
surface./facilitated diffusion of gaseous across alveoli
Distribution:
the linings of blood vessels.
alveoli
mouth cavity
Bowmann capsule
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Simple cuboidal epithelial tissues
Cells are cubical in shape.
View from free
surface are polygonal.
Specialized for
secretion.
Make up the epithelia
of kidney tubules and many glands ± thyroid and
salivary glands.
Simple columnar epithelial tissues
Cells are elongated at right angle to the basement membrane.
Relatively large cytoplasmic volume.
Often located where
secretion or active absorption is an important function.
Distribution:
linings of small intestine( stomach)
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Stratified Epithelial Tissues
Several layer of cells.
With only the lower ones
columnar and metabolically
active.
Division of lower cells
causes older one to
pushed upward forward
surface, becoming
Functions ± only for protection.
Main location ± skin; mouth and vaginal lining.
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Nerve cell
Neurons
± Cell body contains nucleus.
± Dendrites receive signals from sensory receptors. ± Axon conducts nerve impulses.
Any long axon is also called a nerve fiber. ± Covered by myelin sheath.
Types of Neurons:
1) Motor Neurons take nerve impulses from the CNS to muscles or glands.
2) Sensory Neurons take impulses from sensory receptors to CNS.
3) Interneuron convey nerve impulses between various parts of
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Neurons
The pathway of communication between the brain
and the body.
Electrical impulses pass along the neurons from
stimuli receivers to the effectors .
Neurons differ considerably in structure but all
neurons have three things in common;
± Cell body
± Fine cytoplasmic fibre ± dendron or dendrite ± Axon.
The cytoplasm of neurons cell body is
densely packed with mitochondria,
ribosomes, golgi body and rough
endoplasmic reticulum.
Neurons can be classified by their function.
On the basic, there are three types of
neuron;
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Types of Neurons
Sensory
neuron
Motor
neuron
Intermediary/
Relay neuron
A Nerve Cell (Neuron)
Cell Body
Dendrites
Axon of another
Myelin
Sheath
Dendrites of another
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Neuroglia
Supporting cells in the central nervous
system.
There are several types of glial cell in the
brain and spinal cord.
As a group, they do far more than simply
Muscle cell
In the invertebrate body there are three
types of muscle cell;
a) Skeletal muscle.
b) Smooth muscle.
c) Cardiac muscle.
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Skeletal muscle
Attached to the bones by tendons.
Responsible for voluntary movement.
Also called striated muscle.
Smooth muscle
Found in the walls of internal organs ± digestive tract, urinary
bladder etc.
Spindel shaped.
Responsible in involuntary activities.
Contract more
slowly than
65
Cardiac muscle
Form the contraction wall of the heart.
Striated like skeletal muscle but have branched.
The ends of the cells are joined by intercalated
67
Connective tissues
The major types of connective tissues in
vertebrates are:
a) Bone
b) Cartilage
c) Blood
Bone Tissue
The skeleton supporting
the body of most vertebrates.
Bone is a mineralized
connective tissues.
Bone-forming cells
called osteoblasts; deposit a matrix of collagen.
69
The combination of hard mineral and flexible collagen makes bone
harder than cartilage.
Hard mamalian bone consists repeating units called Harvesian
systems.
Each system has concentrate layers of the mineralized matrix, deposited
around a central canal containing blood vessels and nerves that service the bone.
Once osteoblast become trapped in their own secretion , called
osteocytes.
The osteocytes are located in lacunae, space surrounded by the hard
matrix and connected to each other by long thin extensions.
Cartilage Tissue
Has an abundance of collagenous fibers embedded in
a rubbery matrix called chondroitin sulphate.
Chondroitin sulphate and collagen are secreted by
71
Cells confined to scattered spaces
called lacunae in the matrix.
The composite of collagenous fibers
and chondroitin sulphate make cartilage
a strong yet somewhat flexible support
material.
Main locations ; nose, ears, the rings
that reinforce the windpipe,caps on the
ends of some bones.
Blood
Although blood functions differently from other
connective tissues, it does meet the criterion of having an extracellular matrix called plasma.
The plasma consists of water, salts and a variety of
dissolved proteins
Suspended in plasma are two classes of blood cells,
erythrocytes (red blood cells), leukocytes (white blood cells) and cell fragments called platelets.
7 733
Erythrocytes
Erythrocytes
o
o ththe me mosost t nunumermerouous bls blooood ced celllls (s (55 toto 66 million per cubicmillion per cubic
millimeter) millimeter) o
o the the strucstructure oture of thf the ree red bld blood cood cell iell is as anothenother excr excelleellent of nt of structure fitting function.
structure fitting function. o
o a a huhumaman en eryryththrorocycytetes iss is a biconcave disk, thinner a biconcave disk, thinner in the center than
in the center than at its edges.
at its edges. o
o mamammammalilian an ereryyththrorocycytetess lack nuclei an unusual lack nuclei an unusual
characteristic for living cells characteristic for living cells
..
the major function of erythrocytes is to
the major function of erythrocytes is to carry
carry
oxygen
oxygen
..
the small size of erythrocyt
the small size of erythrocytes
es also suits their
also suits their
function ±
function ± the smaller the cells
the smaller the cells
,, the greeter the
the greeter the
total area of plasma membrane
total area of plasma membrane
in a given volume
in a given volume
of blood.
of blood.
the biconcave shape also adds to
the biconcave shape also adds to
its surface area
its surface area
..
erythrocytes
erythrocytes productio
productio
n occurs in
n occurs in
the red marrow
the red marrow
Erythrocytes
7 755
Leukocytes
Leukocytes
5
their collective function is to fight infections in various
ways
monocytes and neutrophils are phagocytes which engulf
and digest bacteria and debris from our own dead cells.
lymphocytes become specialized as B cells and T cells
which produce the immune response against foreign
substances
77
the third cellular element of blood, platelets are fragments of cells about 2 ± 3 µm in diameter.
they have no nuclei.
originate as pinched ± off cytoplasmic fragments of large cells in the bone marrow.
the function of platelets is in the important process of blood clotting.